Lifting jack



Se t. 12, 1933. H. w. CLARK 1,926,711

LIFTING JACK Filed Nov. 30, 1928 2 Sheets-Sheet l 1', I ll INVENTOR .3 Hu w. M,

Sept. 12, 1933.

H. W. CLARK LIFTING JACK 2 Sheets-Sheet 2 Filed Nov. 50, 1928 INVENTORHm w. M

Patented Sept. 12, 1.933

I f 1,926,711 e I nrF'rrNG J CK. v Harold w. Clark; Alliancd' ohio.assignor a 7 "The Buckeye JackManufacturing Company,

AlliancaOhio, a corporation of ohio Application Novmberflli, 1928.." l iS r rzaw V This invention relatesto lifting" jacks, and

particularly 'to lifting jacks of the 1 screw type. t is hereinillustratedand described as applied to'a jack for use with automobiles,although it 0 has numerous other. applications.

In automobile work, particularly with the..advent of the balloon. tire,it is necessary that a jack .-Y. n qa'ver 1ow retracted height. and arelatively high [lift be provided; For this reason if)jacks;of;the',.double screw type have come, into favor. f Suchjacksgwhile they providethe necessary range ofheight and thelowretractedheight,. have been open to numerous objections 'Variou's schemes forinsuring that the severalscrews may,

I be extended to the' utmost have been proposed,

butflmost of them are open to the objectionthat' they are complicated.or are expensive to manu facture...

. A'fur h rd isadvantage a jacksof m sa has been that theeleyatingtmechanism is closev tothe top oil the jack, so thateven alight effort appliedto the handle has been sufficient to turn the jackover; Thisdefect is particularly notieeable on rough roadways. Suchjacks-have.

also been open to the objection that the screws and bearings have beenfunprotected anldfllikel'y to wearand cut on quickly, because of sand andgrit.

I'provide' a jaclr the screw type whichhas I a very low center ofgravity, and in whichthe power is applied near the base, which may bemanufactured at afvery low cost, seam which all oi thQiDZYtSare-adequatelyprotected. The

isnot in any danger oi-getting out of. order.

In the accompanying drawings illustrating the present preferred.embodiment of l the invention, Figure lis a side elevation of the jackpartly broken away, in elevated position;

Fig. 2 .ie -a transverse vertical section through the jack,,the screws.being in retractedlposition; Fig. 3 isatop plan view;

Fig. 4" isahorizontal sectioni-taken on the.

' -line IV--IV .of Fig. 2 and Fig. 5 is a similar view moi Fig-.2. Thejack shown in the drawings comprises a standard 2 0i cylindrical formhaving an integral base 3. The. topfajce ofxthe standard supports'ametalsleeve 6 is welded to thenutas indicated at '2, and .thissleeveextends downwardly over the standard 2, terminating adjacent the base 3,The sleeved is journaledon the standardat. B and 9 so that it isfreelyrotatable thereon, but

35 elevating mechanism is simpleand compact and "high speed.

ake r l hl m ball bearing ewhich ,.in{turn,carries a nut 5. A.

e i in. Sea ease ent" .wiriit ie standard, I

A driven bevel fgearlo' is welded to bottom 0f. the sleeve 6 asindicated .at 1-1. This gge'ar meshes withteeth 12 formed oniorieend of;a driving member 13L The. driving member is io'ur-v naled in abarrel 111 formedgintegral with the j base 3 The'driving member is provided with1 a socket 15 for -the reception: of a.. jack.operati11 the barre1,.fand theprojecting portion on'which the teeth 12 are formed is ofthesame diameter.

The socket lfi jis larger than thebody'portion 1.16 sov that*a..shoulder'bearing'against one end ,of the barrel 14 isiprovidedg. a 4

"By'reas'onj of the fact that the projecting portion carrying the teeth12 .is at least as small in diameter as the body portion 116, thedriving 'rnember 13 may be slid. "into thebarrel. '14. .Q'It is held inplace by a split ring .jl6"which'is pressed into a groove formed in thedriving member after the driving member. has been put-in place. Byreason of. the fact. that the driving mech am'sm is adjacent the base,the centerof gravity of the. jackis materially loweredand the danger vof ltippingthe jack is materially decreased. This is. due not only'tothe low center of gravity, but 1 also theffact' thatthe turning momentapplied by the handle is eiiective very near to the point j ofsupport. 15 The sleeve 6 provides. a very useful effective grip wherebythe nut5.may be rotated for raising or loweringthe'jacklbyhandto anyextentdesjir'ed. .Thismakes it much easier. to, preliminarily adjustthe. jack tonear the desired height, and the raising or loweringflcan beeffected jby hand v at The nut 5 engages aprimarylifting "screw l'l. IThis screw-is movable up or. down. 'within the hollow standardZ and isprovided-with diametri- 9 cally spaced lugs 18 adjacent its bottom.During the intermediate portionv of )the' vtravel of 'the screw 1'7, thelugs 18 are engaged by ribs 19 formed on the inside ofthestandard','which1ribs posi-. tively prevent rotation of the screw 17,whereby rotationjof the nut5 causes the screw .to' raise or lower. Thescrew 17 is'hollow and is threaded at its upper end to accommodatejasecondary screw '20: having a V loadgengaging "saddle '21.- When thescrew :17 reaches the upward limittot its travel, thelugs 18 clear;thetopsof the ribs .19; thus leaving the screw llfree' torotate. The

=upward movement of the screw 17 is terminated by the fact that thethread of the screw'is ter-'- no minated a sufficient distance from thebottom handle. it has'a body portion 16Iwhich lies in its so thatit'locks in the nut just after the lugs 18 clear the ribs 19. Continuedrotation of the nut 5 therefore causes the screw 17 to rotate with it,

and since the saddle 21 is engaged by the load,

thus preventing rotation of the screw 20, the screw is threadedupwardlyfto further raise theload.

When the load is to be loweredfit is, desirable that the secondary screw20 be actuated first. It

sometimes happens that the friction of the small? screw in its nut isgreater than the friction of the large screw in its nut. If such is thecase, the f primary screw 17 reaches thebottom of its travel 'while thesecondary screw '20 is still extended somewhat. Provision is madeforsuc'h occasion,

the primary screw being rotatable in its bottomv position, and beingheld against rotation only by frictional means arranged to opposerotation of the screw more strongly in one direction-than end 23. Duringlowering, the screw 17 tends to rotate counter-clockwise as viewed inFig. 5.

. r When clear of the ribs, such rotation is permitted.

One of the lugs 18 strikes the projecting end 23 of the spring 22 and the'springby reason of the direction in which it is wound, is' relativelyfree to rotate within the standard 2, so that the screw 17 rotates withthe nut 5 and causesflowering of the secondary screw 20. When the jackisraised the screw 17 tends'to rotate ina clockwise direction, as viewedin Fig. 5, but one'of thelugs 18 then strikes the other'fac'eof theprojecting end 23 of the spring. This tends to expand thespringoutwardly, andftlie free'end 24 strongly engages the inner face ofthe standard 2, and provides considerable resistance against rotation ofthe screw .17. This resistanceis sufficient to insure rotation of thenut 5 relative to the screw 17, thus raising the screw to a. point wherethe lugs 18 engage the ribs '19. The lugs 18 are beveled offatjthe topsas indicated in Fig; 4, so as to insure'that they will not lockunderneath the ribs 19. "1 A spring 25, similar in all respects to thespring 22, is placed inthe standard above the ribs 19,-

but inthe "opposite direction as will be seen by a; comparison of FigsAand 5; When the screw 17 reaches the top ofits travel, one of the lugs.18 engages theprojecting end 26 ofthe spring 25 "andby reason of thedirection in which the spring is wound, it is'readily rotated clockwisewith the screw 1-7 as the secondary screw 20 is threaded outwardly.

-When the jacl; is lowered, one: of the lugs 18 engages the oppositeface of the spring end 26,

'whereupon the-free end '27 of the springbears eddownwardly.

strongly against'tlie inn'er face ofthe standard and thus insuresthatthefscrew 1'7 will be thread- I have illustrated and described a presentpre ferred embodiment of the invention as applied to an automobile lack.It will be understood,

however, thatthe'invention is not limited to the form shown',.bu t maybeptherwiseembodied within the scope ofithe following claims.

' 1. A jack comprising a standard, a lifting screw movable within thestandard, arotatable put for raising and lowering the screw, means onthe standard for positively limiting rotation; of the screwrelative tothe standard during a portion of its movement, and friction means forlimiting rotation of the screw during another portion of its movement,including a spring coiled in said standard having means engageable bythe screw te nding'to coil or-uncoil the spring, depending on thedirection "ofscrew rotatior'nso that the spring rotates freely in thestandard or engages it frictionally.

, 2. A jack'comprising a standard, a lifting screw movable within thestandard, a rotatable nut for raising and lowering the screw, means onthe standard" for'positively limiting rotation of the screw relative tothe standard during a portion of its movement," and friction means forlimiting rotation of the screw during another portion of its movement,includinga resilient member lying within said standard having meansengageable by the screw tending to expand or contract the resilthestandard or rotates freely therein.

I 3. A jack comprising a standardya lifting screw movablewithin thestandard, a rotatablc nut forraising and lowering the screw, means forpositively limiting rotation of the screw r elative to the standardduring a portion of itsmovement, and a spring coiled in said standardhaving means engageable by the-screw tending to coil or uncoil thespring, depending on thedirection of screw rotation, so that the springrotates freely in the standard or engages it frictionally.

4. A jack comprising a standard, a lifting screw movablewithin thestandard, a rotatable nut for p raising and lowering the screw,a lug onthe screw,

the standard'being shaped to engage the lug during'a' portion ofthetravel of the screw and limit rotation during such portion of thetravel, and a spring coiled in said standard having means engageable bythe lug tending to coil or uncoil the spring, depending on the directionof screw rotation, so that the spring rotates freely in thestandaid orengages, it frictionally.

5. A jack comprising a standard; a lifting screw, a rotatable nut forraising or lowering" the screw means forypositively' limiting rotationof rection of screw rotation, so 'thatthe springs ro- Itate freely inthe standard or frictionally enage it.

the screw during the intermediate portion of its the screw during theintermediate portion of its I travel, and springs coiled within saidstandard at fthe endsjof' the travel ofthe screw, saidsprings, "having:means engageable by the screw tending ;to coil or uncoil the springs,depending on the ditraveLand friction means for limiting the'rotation ofthe screw atthe 'top and bottom portions of its travel,including'springs coiled within said standard adjacent the ends of thescrewtravel, said springs having means engageable by the screw tendingto coil or uncoil them, depending-- 'on'the direction of screw rotation,so that the springs rotate freely in the standardor frictionallyengageit, therespective springs being effective to engage the standardfrictionally on [rotation of the screw in opposite directions.

'7; ,A jack comprising a standard, a lifting screw, a rotatablenut forraising or lowering the screw, means for positively limiting therotation of the screw during a portion of its travel, friction means'forlimiting rotation of the screw at the top of its travel, including aspring coiled within the standard at the top of the screw travel,"

having means engageable by the screw for coiling or uncoiling the springon rotationofthe screw in opposite directions whereby thespring rotatesfreely in the standard orengages it frictionally to restrain rotation ofthe screw in one direction.

8. A jack comprising a. standard, a lifting screw, a rotatable nut forraising or lowering the screw, means for positively limiting therotation of the screw during a portion of its travel, friction means forlimiting rotation of the screw at the bottom of its travel, including aspring coiled] within the standard having means engageable by the screwforcoiling or uncoiling the spring to permit free rotation of the screwin one'direction and frictionally'restrain it inthe'other'direc'tion.

9. A jack comprising a standard, a lifting screw, a rotatable nut forraising or lowering the screw, means forpositively limiting the rotationof the screw during a portion of its tra'veLfriction means for limitingrotation of the screw at r the top and bottom of its travel, includingsprings coiled within said standard having means engageable by thescrew'for contracting or expandstandard, or; engage it frictionally. 10.The combination: with a nut for actuating the tube, of means forpreventa 3. @ingthem, depending on'the direction of screw V rotation,whereby thesprings rotate freely in the v standard, a threaded tubereciprocable in the standardanda ing rotationofthe tube in the standard.during part of its movement, and a spring coiled in said f standardadjacent one end of the tube travel and having ineansengageable bythetube for coiling or uncoiling it, depending on the *diI'GCtiOII'Of 1,f

tube rotation'gwhereby the spring rotatesfr'eely'j I standard, athreaded tube therein, and'a nut surof tube rotation, so that thespringrotates freely in the" standard or engages it frictionally torestrainrotation of the tube inone direction.

HAROLD w. CLARK.

